Plant control system

ABSTRACT

A plant control system includes: an engineering apparatus for defining change information so as to change definition information about the system; and a control apparatus for referring to the change information downloaded from the engineering apparatus to set an output value of a field device. The control apparatus includes a locking part for inhibiting setting of the output value of the field device.

TECHNICAL FIELD

The present invention relates to a plant control system including anengineering apparatus for changing definition information about thesystem, and a control apparatus for setting an output value to a fielddevice by referring to data change information defined by theengineering apparatus and downloaded from the engineering apparatus.

BACKGROUND ART

A safety control apparatus is known which performs a stop operation of aplant in response to a trip request from the plant at the time ofoccurrence of abnormality, for safe operation of the plant.

FIG. 3 is a functional block diagram showing one example of a plantcontrol system in which a safety control apparatus is combined with adistributed control apparatus. Reference numeral 1 is a plant as acontrolled object, and reference numeral 2 is a control apparatus of thedistributed control apparatus and controls a field device of the plant1.

The control apparatus 2 communicates with a host operation monitoringapparatus 4 through a control bus 3. This operation monitoring apparatus4 is connected to a global communication bus 5 and can communicate withan external PC 6 through the global communication bus 5.

In the plant 1, reference numeral 7 is a field device, which is asafety-controlled object. Reference numeral 8 is a subsystem fielddevice. In the subsystem field device, a large amount of data is managedparticularly among the field devices 7 and field devices (PLC:Programmable Logic Controller, etc.) with relatively low-speedprocessing are grouped.

Reference numeral 10 is an engineering apparatus for changing definitioninformation about a system, and is connected to the control bus 3. Thisengineering apparatus 10 is also connected to the global communicationbus 5 and can communicate with the operation monitoring apparatus 4 andthe external PC 6.

In the engineering apparatus 10, reference numeral 11 is a display parthaving a man-machine interface function, and includes an input-outputmodule definition window 12 and a subsystem data definition window 13.

Reference numeral 20 is a safety control apparatus connected to thecontrol bus 3. This safety control apparatus 20 communicates with theengineering apparatus 10 through the control bus 3 and also communicateswith the subsystem field device 8 and the field device 7 of the plant 1and performs trip processing for performing a stop operation of theplant in response to a trip request from the plant 1.

In the safety control apparatus 20, reference numeral 21 is a functionblock, and sets output values to an input-output module 22 and asubsystem communication input-output module 23. The input-output module22 and the subsystem communication input-output module 23 set the outputvalues received from the function block 21 to the field device 7 and thesubsystem field device 8.

Reference numeral 24 is an input-output module information holding part,and change information inputted from the input-output module definitionwindow 12 of the engineering apparatus 10 is downloaded and is held inthe input-output module information holding part 24. Here, input-outputmodule information means information in which a relation among thefunction block 21, the input-output module 22 and the field device 7 isdefined.

Reference numeral 25 is a subsystem data information holding part, whichis handled by the subsystem communication input-output module 23, andchange information inputted from the subsystem data definition window 13of the engineering apparatus 10 is downloaded and is held in thesubsystem data information holding part 25.

The function block 21 refers to the change information held in theinput-output module information holding part 24 and the subsystem datainformation holding part 25, and then determines and sets output valuesto the input-output module 22 and the subsystem communicationinput-output module 23.

A control system for setting a parameter value to a field device isdescribed in Patent Reference 1.

-   See Patent Reference 1: JP-A-11-110006

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

In the input-output module 22 for mainly handling a contact output, ananalog output, etc., a type or the number of handling data is fixed anda change in input-output module definition is simple, for example,addition or deletion of a card (in the card, information about a fielddevice is reflected and held) of the inside of the input-output module22. As a result of that, a CPU can access the card immediately after thecontents of the input-output module definition are reflected in asystem.

On the other hand, in the subsystem communication input-output module 23for communicating with the subsystem field device 8, the number ofhandling data is larger than that of the input-output module 22 forhandling the contact output etc. and a user can define a type or thenumber of data. In this case, it is requested to change thesedefinitions without stopping a plant.

However, the subsystem communication input-output module 23 exchangesdata with the subsystem field device 8 by Recommended Standard (RS)communication etc. Therefore, it takes a long time to update data whenthe amount of data is large. As a result of that, there is a problemthat continuity of data is not ensured. For example, erroneous data inwhich updating is not completed is referred or set in the case ofaccessing the card immediately after the contents of the definitionchange are reflected in the system.

The present invention has been made in order to solve theabove-described problem, and provides a plant control system forensuring continuity of a plant and ensuring access to an input-outputmodule which cannot be accessed immediately after a changed definitionis reflected in the system in an on-line change of definitioninformation.

Means for Solving the Problems

A plant control system includes: an engineering apparatus for definingchange information so as to change definition information about thesystem; and a control apparatus for referring to the change informationdownloaded from the engineering apparatus to set an output value of afield device, wherein the control apparatus comprises a locking part forinhibiting setting of the output value of the field device.

In the plant control system, the engineering apparatus comprises adisplay part for displaying a locking window for performing a lockingoperation on the locking part.

In the plant control system, the control apparatus and the field devicecomprise a tracking communication part for referring to the changeinformation and checking a present value of a change destination toperform tracking.

In the plant control system, the control apparatus notifies the lockingwindow of completion of the tracking.

In the plant control system, the control apparatus notifies the lockingpart of completion of the tracking.

In the plant control system, the control apparatus is a safety controlapparatus for performing a stop operation of a plant with respect to atrip request from the plant.

In the plant control system, a field device comprising the trackingcommunication part is a subsystem field device.

Effect of the Invention

(1) By combining locking with tracking, an error output to a fielddevice can be prevented at the time of changing data definition of asubsystem.

(2) Since continuity of data in which definition is changed is ensured,the definition can be changed without stopping a plant and thusoperation efficiency can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram showing one embodiment of a plantcontrol system to which the present invention is applied in combinationwith a distributed control apparatus.

FIG. 2 is a functional block diagram showing another embodiment of thepresent invention.

FIG. 3 is a functional block diagram showing one example of a plantcontrol system in combination with a distributed control apparatus.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   1 PLANT-   2 CONTROL APPARATUS-   3 CONTROL BUS-   4 OPERATION MONITORING APPARATUS-   5 GLOBAL COMMUNICATION BUS-   6 EXTERNAL PC-   7 FIELD DEVICE-   100 ENGINEERING APPARATUS-   101 DISPLAY PART-   102 INPUT-OUTPUT MODULE DEFINITION WINDOW-   103 SUBSYSTEM DATA DEFINITION WINDOW-   104 LOCKING WINDOW-   200 SAFETY CONTROL APPARATUS-   201 FUNCTION BLOCK-   202 INPUT-OUTPUT MODULE-   204 INPUT-OUTPUT MODULE INFORMATION HOLDING PART-   205 SUBSYSTEM DATA INFORMATION HOLDING PART-   206 LOCKING PART-   207 SUBSYSTEM COMMUNICATION INPUT-OUTPUT MODULE-   207 a TRACKING COMMUNICATION PART-   300 SUBSYSTEM FIELD DEVICE-   300 a TRACKING COMMUNICATION PART

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail by the drawingshereinafter. FIG. 1 is a functional block diagram showing one embodimentof a plant control system to which the present invention is applied incombination with a distributed control apparatus. The description isomitted by assigning the same numerals to the same elements as those ofthe system described in FIG. 3. Characterizing portions of the presentinvention will be described hereinafter.

Reference numeral 100 is an engineering apparatus. A display part 101having a man-machine interface function includes an input-output moduledefinition window 102 and a subsystem data definition window 103 withthe same functions as those of the above-described system. Theengineering apparatus 100 includes a locking window 104 in addition tothese windows.

Reference numeral 200 is a safety control apparatus, and includes afunction block 201, an input-output module 202, an input-output moduleinformation holding part 204 and a subsystem data information holdingpart 205 with the same functions as those of the above-described system.The safety control apparatus 200 includes a locking part 206 and asubsystem communication input-output module 207 having a trackingcommunication part 207 a in addition to these elements.

Reference numeral 300 is a subsystem field device. The subsystem fielddevice 300 further includes a tracking communication part 300 a forcommunicating with the tracking communication part 207 a of thesubsystem communication input-output module 207 as compared with thesubsystem field device 8 of the above described system.

The locking part 206 is inserted into the middle of an output valuesetting path from the function block 201 to the subsystem communicationinput-output module 207, and output value setting to the subsystemcommunication input-output module 207 is inhibited in a locked state andthe output value setting is performed in an unlocked state.

Locking/unlocking operations of the locking part 206 are performed bymanual operations of an operator via the locking window 104 of theengineering apparatus 100 for communicating with this locking part 206.

Next, a procedure of tracking processing performed between the trackingcommunication part 207 a of the subsystem communication input-outputmodule 207 and the tracking communication part 300 a of the subsystemfield device 300 will be described.

(1) An operator operates the locking part 206 to be in a locked statevia the locking window 104, and inhibits output value setting from thefunction block 201 to the subsystem communication input-output module207.

(2) The subsystem communication input-output module 207 refers to a datavalue, a type and a kind of data targeted for change from the subsystemdata information holding part 205, then sequentially calls the presentvalues of data information referred with respect to the trackingcommunication part 300 a of the subsystem field device 300 from thetracking communication part 207 a, and then allows the present values tobe held in a card of the subsystem communication input-output module207.

(3) The tracking processing ends at a point of completing the calling ofthe present values of the referred data information. The locking window104 is notified of tracking completion notification from the subsystemcommunication input-output module 207. The operator checks thecompletion of tracking, and performs an unlocking operation on thelocking part 206.

(4) By this unlocking operation, the contents of the card of the insideof the subsystem communication input-output module 207 in which thepresent value is reflected by tracking are rewritten by changeinformation by an output value which reflects the contents of change andis passed from the function block 201 to the locking part 206.

FIG. 2 is a functional block diagram showing another embodiment of thepresent invention. The embodiment of FIG. 2 differs from the embodimentof FIG. 1 in that a locking part 206 is notified of tracking completionnotification from a subsystem communication input-output module 207 andthen the locking part 206 automatically shifts its own locked state toan unlocked state and then returns unlocking notification to a lockingwindow 104. In this configuration, an operator performs only a lockingoperation on the locking window 104.

According to the above described embodiments, while the presentinvention is applied to the safety control apparatus 200, it can also beapplied to definition change processing from the engineering apparatus(not shown) to the control apparatus 2 in a distributed controlapparatus. The present application is based on Japanese patentapplication No. 2005-343099 filed on Nov. 29, 2005, the contents ofwhich are hereby incorporated by reference.

1. A plant control system comprising: an engineering apparatus fordefining change information so as to change definition information aboutthe system; and a control apparatus for referring to the changeinformation downloaded from the engineering apparatus to set an outputvalue of a field device, wherein the control apparatus comprises alocking part for inhibiting setting of the output value of the fielddevice, and wherein the control apparatus and the field device comprisea tracking communication part for referring to the change informationand checking a present value of a change destination to performtracking.
 2. The plant control system of claim 1, wherein theengineering apparatus comprises a display part for displaying a lockingwindow for performing a locking operation on the locking part.
 3. Theplant control system of claim 1, wherein the control apparatus notifiesthe locking window of completion of the tracking.
 4. The plant controlsystem of claim 1, wherein the control apparatus notifies the lockingpart of completion of the tracking.
 5. The plant control system of claim1, wherein the control apparatus is a safety control apparatus forperforming a stop operation of a plant with respect to a trip requestfrom the plant.
 6. The plant control system of claim 5, wherein thefield device comprising the tracking communication part is a subsystemfield device.